Feedeeick bahmann



(Model.)

F- BAHMANN FEVER THERMOMETER INVEISTTOBQ ATTORNEY TN ESSES M UNITEDSTATES PATENT OFFICE.

FREDERICK BAHMANN, OF BROOKLYN, NEW YORK.

FEVER-THERMOM ETER.

SPEGIFICATION forming part of Letters Patent No. 244,105, dated July 12,1881.

Application filed April 14, 1881. (Model.)

To all 'whom it may concern Beit known that I, FREDERICK BAHMANN, ofBrooklyn, in the county of Kings and State of New York, have inventedcertain new and useful Improvements in Fever-Thermometers, of which thefollowing is a specilication.

The self-registerin g fever-thermometers heretofore in use were eithermade simply of a graduated tube above the mercury-bulb, in which theindexing-column is separated by a small air-space, or by drawing out theend of the mercury-bulb into a thin tube and bending the same above thebulb into a flat S or loop shaped portion, which latter serves to retainthe indexing-column of mercury and to prevent the return of the sameinto the bulb. The thin drawn-out glass tube is protected by an exteriortube soldered tothe mercury-bulb. Vithin the protecting-tube isarranged, back of the mercury-column, a scale of opaque glass, which issecurely connected to the exterior protecting-tube at the upper end. Theobjection to these well-known forms of thermometers was, that in theformer case the indexing-column of mercury was liable to return into theblub, so as to defeat the very object of the thermometer, while thesecond thermometer was too complicated, requiring too many pieces.

The object of my'invention is to furnish a fever-thermometer in whichthe advantages of both thermometers heretofore described are combined-towit, simplicity of construction and a reliable self-registering of theindexing mercury-column without any liability of its re turning into themercury-bulb 5 and the invention consists of a fever-thermometer havinga graduated upper tube, with a fine center-hole extending through theentire length of the same and sealed at the top, said tube being drawnout at the lower end and bent into a lia-t S or loop shape, andconnected to a second protecting-tube, which contains in its lower partthe mercury-bulb, and which is connectedto the main tube above thefinely-drawnout loop-shaped portion.

In the accompanying drawings, Figure 1 represents a front view, and Fig.2 an enlarged vertical central section, of the lower portion of myimproved fever-therxnonneter.`

Similar letters of reference indicate corresponding parts.

A in the drawings represents the upper or main part of my improvedfever-thermometer, which consists of a graduated glass tube having athin central perforation, within which moves the indexing-column ofmercury. The upper end of the main tube Ais sealed, While the lower endis drawn out into a iine tube, B, and jointed to the mercury-blub C of asecond glass tube, O. Before the drawn-out lower part of tbe main tube Ais jointed to the Inereury-bulb of the tube O it is bent into the shapeofa Eat S or a flat loop, a, as shown in the drawings, which has thewell-known efect of preventing the return of the indexing-column ofmercury into the bulb of the lower protecting-tube, C. The upper part ofthe protectingtube O is sealed onto the lower part of the main tube Aabove the point Where the same is drawn out, so as to inclose the loopedor S- shaped portion and prevent its breakage. The lowerprotecting-tube, C, and the bulb C form, with the main tube A, athermometer ot' uniform diameter throughout, which is fully protected,not liable to breakage, and which preserves in an accurate and reliablemanner the temperature indicated by the highest position of theindexing-column, owing to the fact that the same cannot return into thebulb, but is always reliably kept above the same.

Having thus described my invention, I claim as new and desireto secureby Letters Batent- A self-registering fever-thermometer constructed of agraduated main tube closed at the top and provided at the lower partwith a drawn-out and bent or looped portion, and of a protecting-tubesealed to the main tube above the drawn-out portion, and provided with amercury-bulb at the lower part, which latter is sealed to the lower endof the drawn-out portion of the main tube, substantially as and for thepurpose set forth.

In testimony that I claim the foregoing as Iny invention I have signedmy name, in presence of two witnesses, this 9th day of April, 1881.

FREDERICK BAHMANN,

Witnesses PAUL GOEPEL, CARI. KAEr.

